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UNITE@ STATES PATENT OFFICE.

WALDO H. MARSHALL, OF CHICAGO, ILLINOIS, ASSIGN OR TO THE CONSOLI- DATED BRAKE ADJUSTER COMPANY, OF SAME' PLACE. v

sLAcK-ADJUSTER FOR BRAKES.

SPECIFICATION forming part 0f Letters Patent N0. 518,110, dated April 10, 1894.

l Application filed July 21, 1893. Serial No. 481,101. (No model.)

To aZZ whom t may concern.-

Be it known that I, WALDO H. MARSHALL, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Slack-Adjusters for Brakes;

' and I hereby declare the following to'be a full, clear, and exact description of the same, reference being had to the accompanying draw-` ings, in which- Figure l is a side elevation of devices embodying my invention, shown in connection with a portion of the live lever of a brake system. Fig. 2 is a partial, longitudinal, horizontal section takeny on the line Fig. l. Fig. 3 is a partial vertical section taken ony the line y-y Fig. l. Fig. 4 is a transverse section taken on the line z-z, Fig. 2, looking in the direction of the arrow. Fig. 5 is a vertical section of the end of the bell crank arm or bracket, the latch, pawl, or ratchet, thereof in elevation and on a horizontal axis. of a modification, wherein the latch, pawl, or

Fig. 8 is a view of a brake system for two trucks with intermediate cylinder, showing devices embodying my invention applied to the fulcrum rod between the cylinder levers, and Fig. 9 is a view showing the devices applied to the live lever and lower connecting rod of the truck system.

Like symbols refer to like parts wherever they occur.

My invention relates to that class of devices intended to automatically take up the slack in a brake system to compensate for wear of brake shoes, &c., andVV obviate lost motion.

In fitting brakes to car trucks, it is common to so regulate the lever system andthe various connections thereof with the brake beams, &c., that .only a given or predetermined. movement (which may be termed the normal movement) is thereafter required to apply the brakes; and suchan adjustment of the parts is especially necessary Where only a limited motion of the power mechanism-as for instance in air or steam brakesis permissible. The distance through which the brake shoes must be moved increases- Figs. 6 and 7 are similar views gradually, however, by reason of the wear of the face of the shoe, and owing to this and to other causes giving rise to slack in the system, the brake shoes would ultimately have to be moved a greater distance than the effective stroke of the power mechanism, unless the brake system was adj ustedfrom time to time to take up said slack. To overcome these diiculties, some mechanism which will 6o automatically take up this slack and wear in the brake system is required, and such mechanism must be simple, and easily applied, adjusted, and maintained by comparatively unskilled labor. is the object of the present invention; and to this end my invention-generally statedembraces the combination with a brake lever or equivalentumoving part of the brake system, of a rod or connection leading thereto, a' 7o `nut or turn-buckle in said connection and having external teeth, a bell crank armor bracket mount-ed on the lever or equivalent moving part of the brake system, and a latch pawl or ratchet carried by the bell crank and 7 5` adapted to engage the teeth of the nut or turn-buckle, whereby the abnormal or excessive movement of the lever or equivalent. moving part of the brake system will vary the effective length of the rod or connection so as 8o to compensate for the wear or slack which lias given rise to said excessive movement of 'thei lever or equivalent moving part of the brake? system.

There are other minor features of inventionall as will hereinafter more fully appear.

I will now proceed to describe my invention more fully, so that others skilled in the art to which it appertains may apply the In the drawings A, indicates the truck- 9 beams or other suitable supports fromwhich the brake beamsB are suspended by theusual` hangers b, said beams being provided with brake heads C and shoes c, and having thel 915 usual or any approved system of brake le# vers, connecting rods, and pull-rods. y

In Fig. 8, my devices are shown as applied to the fulcrum rod F and the piston lever P, or on the connections between the brakesysroo tems of two trucks; While in Fig. 9, the devices are shown as applied to the lower con- To meet these requirements necting rod and live lever of a single truck g--this being done, to show that the movement required to operate the devices may be taken from any moving part of the system or particular arrangement of brake levers and connecting rods circu instances may demand. In either case, the connecting rod 1, or equivalent connection may be threaded as at 2, and will carry thereon an internally threaded sleeve or nut 3 provided with peripheral teeth 4, said sleeve or nut 3 having an inclosing case or jacket 5 by means of which it is pivoted on the lever 6, or equivalent moving portion of the systemthe whole constituting one, and the preferred form of adjustable or turn-buckle connection within the brake system. Secured to said lever 6 or its equivalent, is abell crank-arm or bracket 7, one end of which carries alatch 8, adapted to engage the teeth 4 on the periphery of the sleeve or nut 3. This bracket or bell crank lever 7 is preferably pivoted on the center pin 9 by which the jacket 5, nut 3, and connecting rod 1 (or turn-buckle connections) are pivotally connected with lever 6, and the up per arm of the said bell crank lever 7, is provided with an arc shaped slot 10 through which and the lever 6 passes a bolt 11 provided with a nut 12 (or equivalent means is supplied) for regulating the position of the opposite bracket arm which carries the latch or pawl 8 that engages the teeth 4 on the periphery of sleeve or nut 3. The latch orpawl 8 may be on either a horizontal or vertical axis-as preferred. In case it is on a horizon axis, 14, (see Fig. 5) Ipprefer to slot the end of the bracket or bell crank arm as at 15, and use a pawl or latch 8, of general triangular form--or having a tail piece 16-which limits its movement in one direction supporting said latch by a spring 17 which permits the latch or pawl to yield in the reverse direction. Where a vertical axis or latch is preferred,it may be of the same general character, (see Figs. 6 and 7) but should be provided with an inclined face 18 to facilitate its passing the tooth 4, on the reverse motion of the bracket-arm or bell crank.

The devices being constructed substantially as hereinbefore specified will operate as folloWs:-The bell crank arm or bracket 7, having been irst adjusted by means of the slot 10 and bolt 1l (or equivalent means) to bring the latch arm to such position with relation to teeth 4 on sleeve 3, as is demanded by the Iangle of the moving part (or lever) to the connecting rod and the amount of Athe normal movement of said lever or moving part of the system,thereafter, so long as the movement remains normal-there being no wear or slack in the system-the latch or pawl 8 will playback and forth between two teeth 4 of nut or turn-buckle 3, and the spring 17 (or the pawl may be weighted) will permit it to yield without passing a tooth, but so soon as the wear on the brake shoesor slack in the system-permits an excessive movement of the lever (or equivalent moving part) the latch or pawl 8 will ride or be carried past the next tooth 4 of the series and being immediately thrown forward by its springs 17 (or counter balance) will on the return movement of the lever cause the rotation of the nut 3 or turn buckle and thus vary the eective length of the connection (whether the same is a fulcrum rod Fig. S-or lower connecting rod Fig. 9) suhciently to compensate for the Wear or slack in the system.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is

1. In a slack adjuster for brakes, the combination with a moving part of the brake system, of a connection leading thereto and provided with a nut or turn-buckle having external teeth, and an arm or bell crank mounted on the moving part of the brake system and provided with a latch or pawl adapted t0 engage the teeth of the nut or turn-buckle; substantially as and for the purposes specified.

2. In aslack adjuster for brakes, the combination with a brake lever, of a connecting rod having a turn-buckle provided with external teeth, a bell crank provided with a latch or pawl adapted to engage the teeth of the turn-buckle, and a moving part of the brake system on which said bell crank is mounted; substantially as and for the purposes specified.

3. In a slack adjuster for brakes, the combination with a brake lever, of a connecting rod secured to the lever and provided with a turn-buckle having external teeth, and a bracket or bell crank arm having a latch or pawl which engages the teeth of the turnbuckle, said bracket or bell crank arm having a fulcrum coincident with the point of attachment ofthe connecting rod and lever; substantially as and for the purposes specified.

4. In a slack adjuster for brakes, the combination with a brake lever and connecting rod provided with a turn-buckle, of a bell crank mounted on the lever and provided with a latch or pawl which engages the turnbuckle; substantially as and for the purposes specified.

5. In a slack adjuster for brakes, the combination with a brake lever, of a connecting rod having an externally toothed turn-buckle, a bell crank mounted on the brake lever and having at one end a spring latch or pawl which engages the teeth of the turn-buckle, and at the other a slot and bolt adjustment device; substantially as and for the purposes specified. j j

In testimony whereof I affix my signature, in presence of two witnesses, this 6th day of July, 1893.

WALDO I-I. MARSHALL.

Vitnesses:

CHAS. A. BLAKE, NELSON L. LITTEN.

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